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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <!-- 利用函数封装方式 对数组排序 ， 冒泡排序   sort 排序的意思-->
    <script>
        function sort(arr){
            for (var i = 0;i< arr.length - 1;i++){
                for (var j = 0; j < arr.length - i - 1; j++){
                    if (arr[j] > arr[j + 1]){
                        var temp = arr[j];
                        arr[j] = arr[j +1];
                        arr[j +1] = temp;
                    }
                }
            }
            return arr;
        }
        var arr1 = sort([1,4,2,9]);
        console.log(arr1);
    </script>
</body>
</html>